Boiler-feed-water-supply system



' June 30, 1925.

1,543,911 H. FOTHERGILL BUILER FEED WATER SUPPLY SYSTEM Filed Nov. 2, 1922 5 Sheets-Sheet 1 iNVENToQ HAZQY Foru E 6 \LL 1) gnmw W W" W.

June 30, 1925. 1,543,911

H. FOTHERGILL BOILER FEED WATER SUPPLY SYSTEM Filed Nov. .2, 1922 5 Sheets-Sheet 2 BOILER FEED WATER SUPPLY SYSTEM Filed Nov. 2, 1922 3 Sheets-Sheet 5 Patented June 30, 1925.

, siaan PATENT oFFicE.

HARRY FOTHERGILL, 0F WESTMIN$TER, LONDON, ENGLAND.

BOILER-FEED-WATER-SUPPLY SYSTEM.

Application as: November 2, 1922. Serial No. 598,591.

To aZZ whom it may concern:

Be it known that I, HARRY Forr-mnoILL, ofWestminster, London, in the county of Middlesex, England, have invented certain new and useful Improvements in Boiler- Feed-Water-Supply Systems, of which the following is a specification.

This invention has reference to steam condensing and boiler feed water systems oi the kind in which the condensat is removed I from the condenser and delivered to the boilers by rotary pumps.

In systems of this kind it is desirable, in order to promote the satisfactory working of the feed pump, to maintain an approximately uniform pressure on the suction side of such pump, and the object of this invention is to provide means whereby this desideratum may be obtained under all conditions of working, particularly under varying conditions of load, such as when a ship is entering or leaving harbour.

For this purpose I provide means for antomatically throttling or cutting oif the de livery of the feed water on the discharge 1 side of the ieedpump whenever the pressure on the suction side of the feed pump falls below a predetermined limit. say, when from any sudden change or fluctuation in load the pressure on the suction side of the feed pump falls, the delivery of water from such pump is throttled so as to immediately cause, on the suction'side, a use in pressure up to the desired normal, the throttling effect being removed as soon as the supply of water from the condensate pumpis suflicient for, or greater than, the requirements of the feed pump and the pressure in its suction system rises. Means can be provided to admit a supplementary sup ply of water into the system lmmediately the load on the main engine is reduced, so that the throttling oi the feed pump discharge is only of momentary duration and water to the boilers. I

In the accompanylng drawings the invention is diagrammatically illustrated Fig. 1

That is to Fig. 1 is a detail of the valve indicated generally at 8 in Fig. 1.

Fig. 2 is an enlarged sectional View of a portion of the plant illustrated in Fig. 1 and,

Fig. 3 is a diagram of a modified arrangement.

In Fig. l C designates a main condenser from which the condensate is withdrawn by the extraction pump B which delivers through the auxiliary heater D into the suction pipe E of the feed pump 3, which delivers through a heater F to the boilers. Air is withdrawn from the condenser by the steam ejectors G and H, the latter discharging into the auxiliary heater D. J is the filter, K the feed tank and L the reserve feed tank which can be arranged in any convenient manner to suit the requirements of the system. In accordance with my invention this feed pump 3 delivers to the boilers through a throttle valve 1 connected on the delivery pipe 2 from the feed pump 3, and this throttle valve is operated by a piston or equivalent device 4 (Fig. 2) whose movement is controlled by the pressure in the suction system E of the feed pump. A convenient way of controlling this piston l is to provide it with a small hole or permanent leak 5 and subject it on one side to the pressure of the "feed pump discharge 2, the escape of water from the other sideand thus the pressurebeing regulated by a valve 6, such as a needle valve, operated by a spring in one direction and subjected to the pressure on the suction side E of the feed pump in the other direction. An automatic relief valve 8 for the escape of surplus water from the condensate pump into the feed tank-or elsewhere as desired is provided in the feed pump suction pipe.

In order that the working of the apparatus may be understood, it is assumed that the loaded needle valve 6 closes when the does not interfere with the supply of feed pressure in the suction system E acting on the diaphragm 6 rises above ten pounds per square inch, and the relief valve 8 opens upon the occurrence of a pressure of twelve pounds per square inch. When the system is working under normal conditions and the pressure on the suction sid of the feed pump is maintained at between ten and twelve pounds, the valves do not operate and main engines or turbines, the loaded needle valve '6 opens, relieving thepressure on the piston 4 operating the throttle valve "1, and

thus causing such valveto begin to close and reduce the delivery from the feed pump. The pressure on the suction side E is therefore prevented from falling further, and when the supply of water from the condensate pump B increases,th actionis' -reverset and the throttle valve 1 opens wider, ii the supply of water from the condensatepump is greater than that required for boiler feeding purposes, the pressure on the suction side of the feed pump rises until at twelve pounds the surplus water passes through the relief valve 8 into the feed tank.

In order to ensure that a sufiicient supply of water is available at all timesto meet the boiler requirements, as for example when the condensate from the condenser is insuificient for boiler feeding purposes, an automatic by-pass valve 9 or other lniown means is provided to control a supplementary supply of water into the system..

Fig. 3 showsamodified arrangement wherein the throttle valve 1 is a duplex valve held in the closed position as shown in the drawings by a spring 10 when the pressure in the feed pump suction E is below a predetermined'limit but immediately the pres:

sure in the feed pump suction pipe rises this pressure action on the piston 11 operates to open the valve 1 so that the water discharge by the feed pump 3 passesto the'boilers. A relief valve 8- is provided as before in the. feed pump suction pipe also a by-pass valve 9 controlled by the pressure in the turbine and through which valve water can pass from a tank to the condenser C.

In the arrangements illustrated the. bypass valve 9 is similar to that described in Patent No. 1,392,003 and is operated by the pressure in the main turbine-or engine, so that when the load on the main turbine or engine falls below a predetermined amount the valve opens and admits water from the feedor reserve tank into the condenser. Thus, colncident with a reduction in load, there 1S a supplement of water which maintains the supply of water for the boilers,

and, if not required for the boilers, the surplus passes through the relief valve back into the tank.

It will be understood that the apparatus herein described may be constructed inany convenient form providedit will allow of the working above described. For example,

when the throttle" valve is of the balanced 7 .type, another 'piston may be providedfor openlng. it. Also, the throttle valve with its operating piston or pistons may be placed in the same casing, or if desired the throttle and operating piston or pistons may be separate and connected together by suitable mechanism.

lVhat I claim and desire to secure by Letters Patent is 1. A steam condensing and boiler feed water system comprising a condenser, a boiler feed pump to which condensate from the condenser flows, and an automatically operating throttle valve arranged in the system on the discharge side- Of the feed pump, said throttle valve'operating automatically totln'ottl'ethe supply of water from the feed pump" to the boilers-if and when the pressure on the suction side of the feed pump falls below a predetermined value and to remove said throttlingefiect if and when said pressure-rises again, whereby a substantially uniforlnpressure 1s mamtamed on the suction side of said feed pump.

2. A steam condensing and boiler feed water system comprising a condenser, a

boiler feed pump to which condensate from the condenser flows, a throttle valve arranged in the system on the discharge side of the feed pump and adapted to operate automatically to throttle the supply of water from the feed pump to the boilers when the pressure on the suction side of the feed pump falls below a predetermined value and to remove'sai'd throttling effect when said pressure rises again, and a by-pass valve interposed in a connection between a supply tank and the feed system, said valve operating automatically to by-pass water from" the tank to the. system whenever the main engine falls below a predetermined proportion of its full normal load whereby, by the operation of said throttle valve, a substantially uniform pressure is maintained on the suction side of said feed pump and by the operation of the by-pass valve a sufficient supply of water for the boilers is at all times ensured.

i 3. A steam condensing and boiler \feed water system comprising a condenser, a boiler feed: pumpto which condensate from the condenser, flows, at throttle valve arranged in the system on the discharge side 7, of the feed pump and adapted to operate automatically to throttle the supply of water from the feed pump to the boilers when the pressure on the suction side of the feed pump falls below a predeterminedvalue and to remove said throttling effect when said pressure rises again, a tank,a connection between the tank and the feed system, and an automatic relief valve in said connection; op erating to-permit the passage ofan-y excess water'in the syste'mfto said tank 4.,A. steam condensing and boiler feed water system comprising a condenser, a boiler feed pump to whichcondensate from the condenser flows, a throttle valve arranged in the system on the discharge side of the feed pump and adapted to operate automatically to throttle the supply of water from the feed pump to the boilers when the pressure on the suction side of the feed pump falls below a predetermined value and to remove said throttling effect when said pres sure rises again, a tank, a connection be tween the tank and the feed system, and an automatic relief valve in said connection operating to permit the passage of any excess water in the system to said tank, and a by-pass valve interposed in a connection between a supply tank and the feed system, said valve operating automaticallyto bypass water from the tank to the system whenever the main engine falls below a predetermined proportion of its full normal load whereby, by the operation of said throttle valve, a substantially uniform pressure is maintained on the suction sideof said feed pump, and by the operation of the by-pass valve a sufficient supply of water for the boilers is at all times ensured.

5. A steam condensing and boiler feed water system comprising a condenser, a boiler feed pump to which condensate from the condenser flows and an automatically operating throttle valve having a piston whose movement is controlled by the pressure on the suction side of the feed pump arranged in the system on the discharge side of the feed pump, said throttle valve operating automatically to throttle the supply of water from the feed pump to the boilers if and when the pressure on the suction side of the feed pump falls below a predetermined value and to remove said throttling effect if and when said pressure rises again whereby a substantially uniform pressure is maintained on the suction side of said feed pump.

6. A steam condensing and boiler feed water system comprising a condenser, a boiler feed pump to which condensate from the condenser flows and an automatically operating throttle valve having a piston whose movement is controlled by the pressure on the suction side of the feed pump said piston being subject to the delivery pressure of the feed pump on one side, a permanent leak provided in said piston, and a valve permanently loaded in one direction and subject to the pressure on the suction side of the feel pump in the other direction through which water leaking through the piston from the feed system is permitted to escape, the throttle valve being arranged in the system on the discharge side of the feed pump, said throttle valve operating auto- 'matically to throttle the supply of water from the feed pump to the boilers if and when the pressure on the suction side of the feed pump falls below a predetermined value and to remove said throttling eifect if and when said pressure rises again whereby a substantially uniform pressure is maintained on the suction side of said feed pump.

7. A steam condensing and boiler feed water system comprising a condenser, a pump for withdrawing condensate from the condenser, a boiler feed pump. to which condensate from the condenser flows and an automatically operating throttle valve arranged in the system on the discharge side of the feed pump, said throttle valve operating automatically to throttle the supply of water from the feed pump to the boilers if and when the pressure on the suction side of the feed pump falls below a predetermined value and to remove said throttling efiect if and when said pressure rises again whereby a substantially uniform pressure is maintained on the suction side of said feed pump.

In testimony whereof, I aflix my signature.

HARRY FOTHERGILL. 

